I have been restoring a 1989 cbr . It is now ready for an mot . HOWEVER!!! When it is in neutral throttle revs fully BUT!!! When I get past 50 mph doesnt want to go any faster ( As though its fitted with a speed limiter which of course it has not !!) The bike was stood for 3 years so will it sort itself out with use or is there something I have missed? ANY THOUGHTS ? Stuart